Simplify the following expression: $k = \dfrac{10r^2}{2tr} + \dfrac{2sr + 4tr}{2tr}$ You can assume $r,s,t \neq 0$.
Answer: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{10r^2 + 2sr + 4tr}{2tr}$ The numerator and denominator have a common factor of $2r$, so we can simplify $k = \dfrac{5r + s + 2t}{t}$